Core-shell-structured CNT@RuO₂ composite as a high-performance cathode catalyst for rechargeable Li-O₂ batteries

A RuO₂ shell was uniformly coated on the surface of core CNTs by a simple sol-gel method, and the resulting composite was used as a catalyst in a rechargeable Li-O₂ battery. This core-shell structure can effectively prevent direct contact between the CNT and the discharge product Li₂O₂, thus avoiding or reducing the formation of Li ₂CO₃, which can induce large polarization and lead to charge failure. The battery showed a high round-trip efficiency (ca. 79 %), with discharge and charge overpotentials of 0.21 and 0.51V, respectively, at a current of 100mA g_total^-1. The battery also exhibited excellent rate and cycling performance. Get your battery going: Core-shell-structured CNT@RuO₂, a good catalyst for oxygen-reduction and oxygen-evolution reactions, was used to construct a Li-O₂ battery with a low overpotential (0.72V) and thus a high round-trip efficiency (ca. 79 %). By preventing the direct contact of Li₂O₂ with the carbon nanotube (CNT), the uniform RuO₂ coating hinders the formation of Li₂CO₃ to improve round-trip efficiency and cycling performance (see picture).